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Investigation of Thermal Performance of Polymer Composites Reinforced by Graphene/h-BN van der Waals Heterostructures
No full textEffective thermal management has become increasingly critical as modern electronic devices become smaller and more powerful with more functionality. Excessive heat accumulation within these systems can lead to unfavourable thermal stress and performance degradation, thereby reducing the service life of electronic devices. To address this challenge, thermal interface materials (TIMs) are widely employed to dissipate heat and minimize interfacial thermal resistance (ITR) between heat sources and heat sinks. Among various TIMs, polymer-based nanocomposites have gained significant attention due to their lightweight, electrical insulation, and ease of processing. However, the inherently low thermal conductivity (TC) of polymers limits their effectiveness as TIMs in advanced electronics. Incorporating thermally conductive nanofillers has proven to be an effective strategy for enhancing the TC of polymer composites and improving its heat dissipation performance.Graphene and hexagonal boron nitride (h-BN) have proved to be promising candidates for thermally conductive fillers due to their exceptional thermal properties and structural compatibility. Graphene offers extremely high TC and mechanical strength, while h-BN provides high TC along with excellent electrical insulation and thermal stability. The combination of these two materials in the form of graphene/h-BN (GBN) van der Waals (vdW) heterostructures creates hybrid systems with synergistic properties and tuneable thermal transport, making them ideal candidates for next-generation TIMs.This study systematically explores the thermal transport properties of GBN heterostructures and their polymer nanocomposites using a multiscale approach combining molecular dynamics (MD), machine learning (ML), and theoretical analysis. MD simulations were first conducted to explore how various intrinsic and extrinsic factors affect the in-plane TC of three-dimensional (3D) GBN vdW heterostructures. Our results reveal that TC can be effectively tuned by parameters such as hydrogen functionalization, single vacancy, strain effect, interlayer coupling strength, and thickness of outer h-BN sheets, size, temperature. Notably, even 1% hydrogen coverage leads to a significant (~55%) reduction in TC due to enhanced phonon scattering.To broaden the predictive capability beyond atomistic simulations, ML models were developed using datasets derived from MD results. Artificial neural networks (ANN), support vector machines (SVM), and genetic programming (GP) were employed to predict in-plane TC based on key input features. Among the models, the GP model achieved the highest prediction accuracy and provided symbolic mathematical expressions describing the relationship between structural parameters and TC. This data-driven approach supports rapid screening and informed design of GBN heterostructures for thermal applications.In addition to the in-plane TC, the study further investigated cross-plane TC and interfacial thermal conductance (ITC) in multilayer GBN heterostructures. Using MD simulations, the effects of interfacial morphology, including composition gradient, vacancy distributions, isotope doping, and surface functionalization were thoroughly explored. Results show that composition diffusion interfaces significantly enhance ITC (by up to 70%) compared to abrupt graphene/h-BN interface, due to smoother phonon transitions and reduced scattering at the interface. Overall, vibrational density of states (VDOS) and radial distribution function (RDF) analyses further confirm that thermal transport is strongly governed by phonon coupling and interfacial compatibility between adjacent layers.To explore practical applications, the study examined polymer nanocomposites reinforced with functionalized GBN fillers. Reverse non-equilibrium molecular dynamics (rNEMD) and theoretical modelling demonstrate that surface functionalization, using groups such as methyl (-CH₃), hydroxyl (-OH), and carbon doping can significantly reduce ITR between the filler and matrix. Among them, -CH₃ functionalization showed the highest ITC enhancement (~44% at 3% surface coverage) by increasing phonon coupling at the interface. Furthermore, effective medium theory (EMT) was employed to estimate effective thermal conductivity, providing an insight into how filler size, volume fraction, and alignment affect the overall TC of the composite.This thesis delivers both fundamental insights and practical strategies for enhancing thermal transport in next-generation polymer-based TIMs. By integrating MD simulations, ML, and theoretical modelling, it establishes a comprehensive framework for designing nanocomposites with tailored thermal properties. The findings show that interfacial structure, chemical functionalization, and structural configuration can be precisely engineered to modulate both in-plane and cross-plane TC, as well as ITC. This work enables the predictive design of nanocomposites with tuneable thermal performance for modern electronic and energy systems.</p
What Drives Transition from Natural Rubber to Other Types of Farming in Thailand: An Exploratory Study
No full textOver the past decade, Thailand’s natural rubber sector has faced persistent price volatility, weakening global demand, and environmental disruptions, placing growing financial pressure on smallholder farmers. Despite the government’s introduction of price support schemes, these efforts often fail to ensure long-term stability. With approximately 80% of natural rubber exported, Thai farmers remain highly vulnerable to global market dynamics. To address these issues, the government has promoted a shift away from rubber monoculture toward diversified agricultural systems, such as polyculture and agroforestry, through financial incentives and transition support. Yet, adoption remains limited, underscoring the need to understand the multifaceted factors shaping farmers’ decisions. Driven by a deep compassion to support smallholder farmers and reduce their vulnerability, this study investigates transitions from rubber monoculture to alternative systems including rubber-agroforestry, mixed farming, integrated livestock, and high-value crops. Adopting a constructivist paradigm and abductive logic, it combines Q-methodology with Bottom-Up Qualitative Comparative Analysis (QCA) to uncover both subjective perspectives and causal complexity. Guided by Social Exchange Theory (SET) and Theory of Change (ToC), the study introduces a dual-framework lens. SET explores how farmers assess perceived benefits and trade-offs, while ToC focuses on how they understand and enact change based on enablers and expected outcomes. Q-methodology identifies four groups of transited farmers, including Security Seekers, Trend Followers, Optimum Finders, and Profit Seekers. It also distinguishes five groups of non-transited farmers, including Believers, Financial Strugglers, Climate Worriers, Risk Averters, and Co-op Seekers. While both groups share common drivers such as food security, profitability, and reduced income uncertainty, some key differences emerge. Transited farmers highlight cost savings and practical advantages, whereas non-transited farmers express concerns around health and familiarity with existing practices. Both groups recognise income dependence on rubber and threats like Abnormal Leaf Fall (ALF) disease as barriers, while key enablers include awareness of support, availability of labour, and commitment to change. Bottom-Up QCA reveals five distinct pathways: three for transited farmers (Motivated Learners, Labour-Driven Profit Seekers, Food Security-Focused Adopters) and two for non-transited farmers (Knowledge-Driven Traditionalists, Income-Security Seekers). The integration of Q-methodology and QCA not only validates findings across methods but also proposes a robust SET–ToC framework. This offers policymakers deeper insights into aligning interventions with both contextual enablers and farmers’ internal motivations for sustainable agricultural transitions. This study contributes theoretically by extending SET to include non-economic dimensions like health, wellbeing, and environmental values. Practically, it offers a transferable decision-making model for designing farmer-centred interventions tailored to diverse profiles. Future research could explore the role of trust and social learning in transition processes using social network analysis, offering new insights into peer influence and information diffusion in agricultural change.</p
Unsteady analysis of the airflow in human nasal airway – a computational study
No full textBackground and objective: Nasal cavity is the first line of defence against toxicants and pollutants. A deep understanding of the realistic airflow in the complex geometry is crucial to evaluate pollution impact and initiation of various respiratory diseases. Human respiration by nature is unsteady, having two phases – inhalation and exhalation. While prior studies are predominantly on the steady state considering only the inhalation phase, we are curious to understand and investigate the unsteady nature of human respiration. Methods: A sinusoidal unsteady profile simulating a complete breathing cycle at a flow rate of 10 L/min is considered in this study. We have reconstructed a realistic human nasal cavity model from CT scans and with Ansys Fluent we have analysed the flow field. The time-evolving flow patterns and wall shear stress, in particular during the distinctive accelerating and decelerating breathing phases, are extracted. Critical transient insight to the unsteady breathing which is largely unknown in a steady simulation is revealed. Finally, the breathing air flux in the olfactory region are calculated under the transient breathing condition. Results: Evolving flow pattern at different time instants gives a significant variation of the flow dynamics which would not be understood in a steady study. The main differences in inhalation and exhalation are the regions where the main flow is dominant, the location of the vortices around the olfactory and wall shear stress patterns. In addition, past history of peak flow has noticeable effects on flow fields during the deceleration phase, especially when the breathing rate is low. Finally, flow pathways into the olfactory region varies during inhalation and exhalation phases. Conclusion: The cyclic information provides critical transient insight to the unsteady breathing which is largely unknown in a steady study. In the context of a fast-growing interest in nasal transport to accurately evaluate pollution impact and pathogen deposition, investigation on the flow and particle depositions under unsteady condition is valuable and highly desired.</p
The Domino effect of risks on supply chain performance in disruptive times
No full textGiven the recent global disruptions such as the pandemic and the geo-political conflicts, there is a growing interest in how risks propagate within supply chains, influencing the structural design and planning. An empirical study involving 207 Vietnamese construction enterprises assessed the significance of the Domino effect, where multiple risks interact and amplify one another’s impact. The research utilized a novel comparative model based on the individual effects of each risk on SC performance to validate the proposed theoretical model of the Domino effect. The model explains 66% of the variance in SC performance, surpassing the comparative model and prior research. The study revealed that the Domino effect triggers disruptions that cascade downstream and affect SC performance, leading to supply instability, operational challenges, innovation inefficiency, and loss of market share, etc. The research leverages empirical evidence from the pandemic and geopolitical conflicts to enhance understanding of the SC structural dynamics during turbulent times. Finally, it provides strategic risk mitigation approaches to enhance resilience in the Vietnamese construction industry and ensure robust preparedness for future disruptions.</p
Experiences of CALD Women, Service Providers and Interpreters in Domestic Violence Settings: A Need for Specialisation?
No full textCulturally and Linguistically Diverse (CALD) women in Australia face multiple, intersecting barriers when accessing domestic violence response services. These include financial insecurity, limited knowledge of legal rights, immigration status concerns, and social isolation. Language access remains one of the most significant barriers when seeking help. Concerns related to language services in domestic violence settings have been raised in Australia over the past three decades. Although Australia is recognised as a leader in community interpreting these concerns persist, and there is no coordinated specialist approach to interpreting services in domestic violence contexts. Interpreters remain excluded from sector-wide and integrated responses, despite their critical role in enabling CALD women’s access to justice and support services. This research aimed to examine the need for specialist interpreting services in domestic violence settings in Australia, with a focus on the experiences of CALD women, service providers, and interpreters. The study sought to identify challenges associated with interpreter-mediated communication in these settings, as well as the broader systemic and inter-sectoral factors shaping access to services. The methodology was informed by qualitative feminist research principles and a critical interpreting approach. Data collection tools included interviews with CALD women, focus groups with services providers and an online questionnaire and interviews with interpreters which provided rich and in-depth information from participants. This research found complex and intersecting issues including those related to the system of language service provision, interpreter competence and the lack of inter-sectoral understanding. These issues had a range of serious consequences for CALD women, including unjust legal outcomes, limited protection for them and their children and disrupted access to services. Addressing these challenges requires a collaborative response grounded in the understanding that quality communication is a shared responsibility. The research argues that specialisation in domestic violence interpreting requires broader systemic reforms, including the creation of a registry of specialist interpreters, mechanisms to ensure continuity of care and inter-professional briefing and debriefing, and increased availability of female interpreters. Furthermore, this study argues for the integration of interpreters into the domestic violence multi-agency sector. Such integration would support collaborative professional engagement, ensuring shared understandings of domestic violence and of the range of professional settings with the sector, thereby fostering the conditions necessary for interpreter specialisation. The research concludes by presenting a number of policy and practice recommendations to support the implementation of specialist interpreting services in domestic violence settings. The research contributes to both the emerging subdiscipline of domestic violence interpreting and the limited body of feminist research in Interpreting Studies.</p
Near-Infrared Colour Centres in Diamond for Bioimaging and Sensing
No full textColour centres in diamond and other wide bandgap semiconductors have received increasing interest in recent decades for their promising applications in quantum metrology, bioimaging, and quantum computing. However, colour centres in diamond which emit in the near-infrared (NIR), especially at wavelengths above 1000nm, where optimal transmission windows exist, have not been well studied. Indeed, until the novel colour centre described in this thesis, there were no confirmed colour centres in diamond with a zero phonon line (ZPL) longer than the 1042nm 1A1→1E transition observed from the negatively charged nitrogen-vacancy (NV-) colour centre.
This thesis reports the observation and characterisation of two NIR colour centres in diamond. Firstly, a newly reported centre seen in silicon-doped diamond with a ZPL at 1221nm. Photoluminescent (PL) characteristics of this colour centre observed in high-pressure hightemperature (HPHT) diamond particles is reported. The potential identity of this colour centre is also evaluated.
An in-depth study of the temperature dependence of the PL from the 1221nm centre is presented, and a number of methods to determine the temperature from the observed PL are reported. Due to the well-defined and easily resolved PL features being located in the second biological window (1000–1350 nm), this colour centre has potential for biological sensing and imaging applications. To demonstrate this, the 1221nm colour centre is shown to be an effective thermometer for use with electronic devices and for biological specimens. While the sensitivity is comparable to other diamond-based all-optical thermometry approaches, the emission wavelength and easily resolved spectral features commend it as an NIR thermometry platform.
New results from the negatively-charged dinitrogen-vacancy (NVN-) centre (ZPL at 986nm) are also reported. Despite being first observed over 50 years ago, the NVN- centre has been studied very little. For the first time, NVN- has been observed in untreated HPHT diamond. The ubiquity of this colour centre in untreated HPHT diamond is demonstrated. As well as these observations, the NVN- centre is also seen for the first time in untreated HPHT micro and nanodiamonds, as well as in detonation nanodiamonds (DND). A study of the emission intensity and spectral shape as a function of particle size is presented. A positive correlation between substitutional nitrogen concentration and NVN0 and NVN- centres is also shown. As well as nitrogen concentration, the influence of HPHT growth sector on NVN- concentration is described. Finally, a characterisation of the NVN- PL lifetime and power saturation are discussed.
This thesis extends the understanding of diamond colour centres by uncovering and characterising novel NIR emitters. The investigation into their photoluminescence properties not only fills a significant gap in current literature but also highlights their promising potential for applications in quantum sensing, bioimaging, and telecommunications. These findings lay a robust foundation for future studies aimed at furthering research into NIR colour centres in diamond and harnessing their properties for sensing and imaging technologies.</p
The Effects of Human Resource Strength and Social Identification on Employee Performance: The Case of Bangladeshi Private Commercial Banks
No full textThis study was carried out in two private commercial banks in Bangladesh. The purpose was to examine the effects of HR strength on the social identification of employees through the interactions of employees with their line managers and relationships within work groups and ultimately employee performance. Underpinned by social identity theory, we tested three hypotheses using 436 respondents. Findings confirmed our hypotheses: social identification mediated the relationship between HR strength and employee performance; social interaction with the line manager and social identification sequentially mediated the relationship between HR strength and employee performance; and the quality of relationships within the work team and social identification sequentially mediated HR strength and employee performance. We contribute to new understandings of the role of social identification processes in explaining the link between HRM and employee performance in high power distance and collectivist cultures. Implications are drawn for HR managers by demonstrating the role of HR strength and social identification in supporting employee performance.</p
Test Record for Author Crosswalk FIG to ELE 20250807 KC
No full textThis test record is for the purpose of testing the FIG to ELE crosswalk for author Keely Chapman on 20250807. </p
Not a Symptom of Employment
No full textResearch background Published in Extra‑curricular: On and around the topic of self‑organised learning, curriculum, experiments, and alternatives in graphic design education (Onomatopee 163, ed. Jacob Lindgren, 2018; 328 pp; ISBN 978‑94‑91677‑92‑2). The reader assembles international contributions on alternative pedagogies in art and design and the author was invited to write "Not A Symptom of Employment" by the editor due to the wide-reaching success of the class in question.Research contribution The chapter articulates an approach to pedagogy that foregrounds practice. It examines a unit of study written and delivered by the author at MADA since 2015, namely the elective unit cds2524 Unconventional Publishing. The class engaged students to think critically about the nature of practice and that it might be envisioned as valuable even outside of the context of employment. It detailed a number of extra-curricular projects enacted by members of the class.Research significance Onomatopee is a recognised international publisher; the volume had wide distribution (Artbook | D.A.P., Perimeter, Walther König, etc.). Library holdings are extensively international and include RMIT University Library, evidencing international reach and durable access.</p
Six Tales of Animals and Five Related Essays and Projects - Piecing Cities Together by Taking their Objects Apart
No full textUnimaginable global events ripple through time, embedding themselves in daily life across multiple scales, distance, memory, and speed. They fracture coherence, disrupt narratives, and reshape shared realities. Within this shifting landscape, this study revisits broad questions: How do we observe, gather, reimagine, and narrate the built environment through acts of assembling fragments, searching for new associative meanings? Can we piece together a collage of histories and future memories, mapping the echoes of what was, what remains, and what might emerge? This PhD research practice is centred on object assembly and collage-making in relation to storytelling. How can these methods allow us to retell the environment, both in the familiar and the unseen? How can the fabrication of objects help suspend time, allowing liminal space to exist between the real and the imagined, past and present, fiction and history? Drawing upon art, architecture, and cities, I piece together cultural landscapes that merge detailed accounts with artistic expression. In this process, writing becomes a site of negotiation, between clarity and ambiguity, precision and the beauty of imperfection. My interest in art, architecture, and cities revolves around representation as a way of seeing and reinterpreting cultural landscapes. This PhD has taken shape through cities that have influenced my architectural knowledge and artistic practice. The discipline developed through academic exercises, paired with the opportunities to express my perspective through art projects, has always sought to articulate core ideas through writing. Yet writing has remained an unresolved challenge, caught in the paradox of clarifying what words can never fully explain. Language often risks becoming overly metaphorical, excessively subjective, or romanticised. Yet imperfection is its strength, showing how to write without fixing, how to frame without closing, how to hold things in suspension. This dissertation is structured as a series of thoughts, collections of essays, stories, and tales. Loosely bound, these pieces invite the reader to make their own connections, resisting fixed conclusions. Piecing together a city is an act of unpacking the knowledge embedded within it, learning from cities, learning how to learn. By remaining open to the experiences and insights these cities offer, I allow them to shape both my understanding and my approach.</p